I got a loaner from my dealer today while my car is being serviced.

The loaner is a 2011 MCS automatic. I notice that cruising at 70mph the rev counter shows approx 2200.

In my car a 2009 JCW manual at the same speed the rev counter shows approx 3000.

Does this seem right?

 

And your question is?

 

i'm just surprised that there would be that much difference in the rpms at the same speed

 

Two entirely different gear boxes with different gear ratios through all six speeds. Each will have a different cruising speed at the same gear. I don't have an automatic, so I'm not sure if the auto also has an overdrive gear.

Funny you ask this, as I was thinking to myself on a recent Vegas trip that it would be nice to have a lower 6th for long, steady freeway cruising. One of the things I loved about the gearbox of a Corvette is that you could go 80 and only be running the engine at 1800 rpms or so.

Another speed factor could be tire diameter...was the auto the same as your JCW?

 

Guess you would need to look at the gear ratios between your 2009 manual and 2011 auto. I've experinced similar phenomenon with VW in the past, automatics rev lower at highway speeds.

 

My 2006 auto and GP manual showed pretty much the same differences.

You could argue the auto is ready to shift when needed while the manual is maintaining higher revs to reduce your need to manually shift on the highway.

 

My son has an 09 MCCS auto and I have an 11 MCS manual and we have noticed the same difference. One would think that would effect gas mileage, expecting the manual running 70 mph at 3000 rpm to be less efficient than the auto running 70 mph at 2200 rpm, but our experience is just the opposite. I have achieved close to 38 mpg with steady cruising at 70 mph while the best my son can do is 36 mpg under the same scenario. I suspect that has more to do with the Clubman being just that much heavier. At any rate, what you experienced is normal.

 

My 2008 manual seems to gets its best mileage right at 3000 rpm down to 2800 and it drops off by about 4% and the lower I go the worse it gets

 

I agree, 2800 - 3000 rpm does seem to be the sweet spot in these cars with the manual transmission, especially for good mileage. It also seems to be the torque / power sweet spot. When I "punch" it to pass someone the throttle response and power are there immediately. I am not an automotive engineer or techie, but my sense is the turbo is spinning just enough at 2800-3100 rpm that the engine is getting the full benefit of forced induction without sucking in a lot of extra fuel, and it is also spinning just enough that there is no turbo lag with increased throttle. Even cruising in 3rd, 4th or 5th gear, I now resist the urge to drop the revs by grabbing the next gear and just try and keep it at 2800-3100 rpm.

 

Interesting....so at say 50mph I shouldn't drive in 6th thinking its better mpg than just staying in 5th? That's counter intuitive but Ill have to some how test it out.

 

thanks for the comments and insights guys.

I wondered if cruising at 2200 rpms would be easier on your engine than cruising at 3000 rpms especially on a long trip. Coming back from the dragon almost the entire length of I81 in Virginia (~300 miles) at 75mph or better. Seems the higher revs would be more wear on the engine but i really don't know.

Not really much i can do about it.

@Mo'Phat - My car has 17" tires - the loaner has 16"

 

They JCW is geared higher for performance. At 3000 rpm the speed should be exactly 75mph in 6th. This is why the JCW MPG is less then the S. Also I think the Germans gear their performance cars so they can achieve the highest top speed in the top gear.